Each server blade includes a 633MHz Transmeta CPU, up to 512MB RAM, one or two laptop-sized IDE hard drives and three Ethernet interfaces, one of which is reserved for the management network while the other two are available for applications. Each server blade uses 7 watts idle or 15 watts under load, making a fully populated 24-server 324 consume less power than the three 1U servers it replaces on the rack. It's no disk or CPU powerhouse, but it is more than adequate for web and other network applications.

RLX's default Linux load is Debian-based, with Transmeta-specific tweaks. The company also offers the 324 with Red Hat Linux or with legacy Microsoft Windows 2000, and for a small one-time fee, they will ship servers with customer-provided loads. RLX currently has a proprietary, binary-only kernel module for access to hardware monitoring features, and field systems engineer Brian Towles said they have not yet decided whether or not to release it under a free software/Open Source license. Proprietary, binary-only kernel modules give a lot of Linux professionals the heebie-jeebies, though, but it is possible to run without the proprietary modules, Towles said.

The 324, front to back, consists of a locking door with a lit-up logo, 24 green LEDs, two seven-segment displays and six fans. Behind the door, up to 24 vertical server blades are located, each about the size of a full-size PCI card. All blades plug in to a common midplane board. Behind the midplane are two redundant power supplies, one in each rear corner. In the middle of the back panel are four communications cards, each with one RJ21 connector, and one internal hub for the management network. Users can set the seven-segment displays to arbitrary values with DIP switches. The RJ21 connectors let users connect the 324 to a compatible Ethernet switch using only four cables instead of 48.

There are no keyboard or video connectors, and server blades boot off the Net using the Intel PXE protocol. A front-panel serial port on each blade provides access to a serial console.

Among the applications being tested are Scyld's Beowulf software; Scyld has been running a 220-node cluster all in one rack. The 324 will be available direct and through IBM.